CHARACTERIZATION OF A MODIFIED 2-STEP FURNACE FOR ATOMIC-ABSORPTION SPECTROMETRY FOR SELECTIVE VOLATILIZATION OF IRON SPECIES IN HEMIN

A two-step furnace was modified by eliminating contact between the cup furnace and the integrated contact cuvette (ICC), thus maximizing the independence of the temperature control of the two components, Optimi zed cup and ICC temperatures were determined for Cd, Cr, Cu, Fe, and P b. Efficient analyte transportation (--> 91%), from the cup to the ICC , was observed for an ICC-cup separation of up to 3 mm. Analyte transp ort was aided by an apparent convective flow of Ar into the hole in th e bottom of the ICC, Despite this flow, the loss of Cd and Ph from the furnace appear to be limited by diffusion. The relative sensitivity f or the modified two-step furnace was approximately 50% worse than that for the same ICC with atomization from a platform, Iron in a porphyri n complex (heme Fe) gave two absorbance peaks at approximately 300 deg rees C and 2000 degrees C. Use of two-stage volatilization (the furnac e temperature was held constant while the cup was heated to 300 degree s C and then 2000 degrees C) produced both peaks from a single atomiza tion.